The conventional game racket frame is generally formed of one hollow tubular body of fiber reinforced plastic and is therefore limited in its capability to withstand the side stress when the ball-striking face of the head of the conventional game racket is impacted on by a ball, especially at such time when the ball is smashed. As a result, such a conventional game racket frame is vulnerable to severance when the string of the head of the game racket is impacted on by the ball, in view of the fact that the side stress exerting on the game racket frame by the string is greater than the load of the hollow tubular body of which the game racket frame is formed.
An improved version of the game racket frame is disclosed in the U.S. Pat. No. 5,516,100. The game racket frame is formed of a main body consisting of two laminated tubes of fiber reinforced plastic. The main body is provided with a reinforcing rib located between the adjoining walls of the laminated tubes so as to enable the main body to endure a greater intensity of side stress. In fact, the main body which is reinforced by the reinforcing rib is incapable of withstanding the side stress effectively in view of the fact that a stress concentration tends to take place at both sides of the reinforcing rib, and that a strip is embedded in the reinforcing rib. The strip is made of a material different from the material of which the reinforcing rib is made. As a result, the structural integrity of the main body is undermined by the strip. In addition, the structural strength of the racket frame is compromised by the strips which are located at the junctions of the two laminated tubes so as to eliminate the work of providing the racket frame with the string holes. The strips are in fact rather vulnerable to deformation caused by the internal pressure which is brought about by the fluid injected into the laminated tubes at the time when the process of making the racket frame is under way.